Rotorcraft Downwash Flow Field Study to Understand the Aerodynamics of Helicopter Brownout

Abstract

Rotorcraft brownout is caused by the entrainment of dust and sand particles in helicopter downwash, resulting in reduced pilot visibility during low, slow flight and landing. Recently, brownout has become a high-priority problem for military operations because of the risk to both pilot and equipment. Mitigation of this problem has focused on flight controls and landing maneuvers, but current knowledge and experimental data describing the aerodynamic contribution to brownout are limited. This paper focuses on downwash characteristics of a UH-60 Blackhawk as they pertain to particle entrainment and brownout. Results of a full-scale tuft test are presented and used to validate a high-fidelity Navier-Stokes computational fluid dynamics (CFD) calculation. CFD analysis for an EH-101 Merlin helicopter is also presented, and its flow field characteristics are compared with those of the UH-60.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Oct 01, 2008
Accession Number
ADA509010

Entities

People

  • Alan J. Wadcock
  • Eduardo Solis
  • Ganesh Rajagopalan
  • Lindsay A. Ewing
  • Mark Potsdam

Organizations

  • National Aeronautics and Space Administration

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aircraft Equipment
  • Aircrafts
  • Airframes
  • Computational Fluid Dynamics
  • Control Systems
  • Downwash
  • Flow
  • Flow Fields
  • Fluid Dynamics
  • Fluid Flow
  • Ground Effect
  • Ground Level
  • Helicopters
  • Particles
  • Photographs
  • Rotary Wing Aircraft
  • Shear Stresses

Readers

  • Aerodynamics.
  • Aviation Safety Risk Assessment.
  • Computational Fluid Dynamics (CFD)